The CCR-Flow Core is an indispensable resource for NCI and contractor investigators at the Frdereick National Lab for Cancer research. Investigators have used the expertise of the flow core staff and the instrumentation available and maintained by the staff to investigate the role of various interleukins and tumor necrosis factor in tumor biology and the role of the inflammatory response in tumorogenesis. Another lab is investigating the basic biology of tumor stem cells. Other labs are investigating mechanism of differentiation of mouse bone marrow stem cells. Other labs are investigating the role of natural killer cells in the recognition of human leukocyte anigen B and the role of kir3DS1 in HTLV-1 infection.The flow core staff has trained eighteen investigators in the first three quarters of the year to run their own samples. The instruments are used daily by the trained investigators often into the night and on the weekends. This leaves more time for the flow core staff to sort approximately 550 samples and analyze about 7700 samples in the first three quarters of this year. Without the investigators acquiring the data and analyzing their own samples, the government would have to hire full time experienced individuals to perform the same volume of work. At least 19 papers have been published in the past year using data obtained in the flow core. In the past year, data has been generated (or samples have been sorted) for 79 individual scientists from the laboratories of 41 principal investigators. Although the CCR-Frederick Flow Cytometry Core is part of the CIP, investigators from this program account for approximately 27% of the use of this facility.The future goals include keeping up with cutting-edge technology in the flow lab by expanding the pool of investigators trained to run and analyze their own samples to all of CCR in Frederick thereby expanding the use, productivity and quality of the science generated using the core's instrumentation and expertise. This could be achieved by adding a 405 laser to the LSRII Fortessa and replacing the two BD FACScans with small 2 laser 6-color instruments.